Light color, low softening point hydrocarbon resins

ABSTRACT

A light color optionally hydrogenated petroleum hydrocarbon resin including an aromatic hydrocarbon component useful for tackifying block copolymers is described which has a softening point of about 0° C. to about 40° C., a number average molecular weight (Mn) of from 350 to 600 and a molecular weight distribution (Mw/Mn) of from 1:1 to about 2.0.

CROSS REFERENCE

This application is a continuation-in-part of U.S. patent applicationSer. No. 830,409, filed Feb. 18, 1986 now U.S. Pat. No. 4,677,176.

This invention relates to a hydrocarbon resin having excellenttackifying properties in adhesives. More particularly, it relates to ahydrocarbon resin having aromatic components with light color and asoftening point of about 0° C. to about 40° C.

BACKGROUND OF THE INVENTION

Adhesives form a large part of daily activity for everyone, whether inthe form of tape used to close a package or secure items together,bandages, envelopes, notepads, diaper tabs or any one of many otherproducts in common use. The key requirements for adhesives are that theyshould have suitable cohesive and adhesive properties at end useconditions and during application, whether by solvent or bulk casting.Usually these adhesives are prepared from a mixture of resin, copolymerand a plasticizer to soften the adhesive and enhance tack.

Adhesives prepared from blends incorporating these polymers have verygood adhesive and strength properties at room temperature and can beprocessed by conventional melt coating and extrusion techniques becauseof their good flow characteristics. Because of the excellent combinationof properties exhibited by certain copolymers of a diolefin or an olefinand styrene, the use of such polymers for various pressure sensitiveadhesive applications is growing in the industry.

Copolymers made from polystyrene and a diolefin are widely used in theproduction of adhesives such as, for example, styrene/isoprene/styrene(SIS), styrene/butadiene/styrene (SBS), andstyrene/ethylene/butylene/styrene (SEBS), and the like. All of thesecopolymers whether formed by polymerization of polymer block or byrandom polymerization, are blended with tackifying resins in order toform the adhesive.

However, when copolymers are mixed with tackifying resins in order toform adhesives, many requirements and factors are important such as theease with which the resin is blended with the copolymer and the controlof the tack as well as the long term properties of the adhesive.Further, the adhesives industry has increased the demand for lowsoftening point resins and market requirements dictate the desirabilityof resins which are not only liquid, i.e., softening point about 40° C.or less, but that are light in color, even a Gardner color of less thanabout 3. However, a resin would be considered to be sufficiently lightin color for some applications with a Gardner color of 6 or even 7.

Many attempts have been made to prepare resins having these propertiesfor use in the blending with copolymers to form adhesives, but all havefallen short of the mark in one respect or another. While other attemptshave been made to prepare light color, low softening point resins suchas those described in, for example, U.S. Pat. Nos. 3,963,653; 3,931,125;3,574,792 and 4,078,132, most attempts have been centered around thepreparation of aliphatic resins of the type described, for example, inU.S. Pat. Nos. 3,813,357; 3,692,756; 3,661,870; 3,804,788; 3,853,826;3,872,064; 3,098,983 and 4,153,771. Unfortunately, aliphatic resins donot provide desired adhesive properties with many copolymers. Othercomponents are required, usually an oil such as a naphthenic oil forexample, to impart the tack or other requisite adhesive properties tothe adhesive. The presence of the oil itself can cause detrimentaladhesive performance. The liquid resins containing aromatic componentssolve these problems.

Prior attempts to incorporate aromaticity into the resin have generallycaused an unacceptable high color level to result, thus making theresulting adhesive unsuitable for various uses.

Accordingly, it is an object of this invention to provide a lowsoftening point hydrocarbon resin; i.e., from 0° C. to about 40° C.

It is a further object of this invention to provide a low softeningpoint resin having a light color while including aromatic substituentsto enhance adhesive properties.

Non-aliphatic resins having very low color exist even to the point ofbeing water white. To use these resins to blend with some copolymers toform pressure sensitive adhesives, resins containing some aromaticityand light color, are desired. The presence of an oil plasticizer cancause detrimental results to substrates to which the adhesive isapplied. Attempts to incorporate aromaticity, and thus compatibilitywith the styrene portion of copolymers, into the resin have generallycaused an unacceptably high color level making the resulting adhesiveunsuitable for various uses.

Accordingly, it is an object of this invention to provide a pressuresensitive adhesive incorporating a low softening point, from 0° C. toabout 40° C., and light color aromatic-containing hydrocarbon resin.

It is a further object of this invention to provide adhesives in abinary or tertiary system of a copolymer and a low softening point resinhaving a light color even while including aromatic substituents toenhance adhesive properties.

SUMMARY OF THE INVENTION

We have discovered a light color, low softening point resin polymerizedin a Friedel Crafts reaction from a feed stock comprising: (a) fromabout 5% to about 75% by weight of C₈ to C₁₀ vinyl aromatic hydrocarbonstream; (b) up to about 35% by weight of a piperylene stream; and (c)from about 25% to about 70% by weight of a stream containing C₄ to C₈monoolefin chain transfer agents of the formula RR'C═CR"R"' where R andR' are C₁ to C₅ alkyl, R" and R"' are independently selected from H anda C₁ to C₄ alkyl group. The resins have a weight average molecularweight (Mw) of 110 to about 1600, a number average molecular weight (Mn)of 100 to 600, a (Mw)/(Mn) ratio of from 1.1 to about 2.7, and asoftening point of from 0° C. to about 40° C. The resin can be blendedwith copolymers to provide useful adhesive compositions. The molecularweights are measured by a gel permeation chromatograph using apolyisobutylene standard and appear as mono-modal peaks on thechromatograph chart.

Thus, in accordance with this invention there is provided a hydrocarbonresin containing a major proportion of the catalyzed polymerizate havinga number average molecular weight (Mn) of from 100 to 600, a weightaverage molecular weight (Mw) of from about 110 to about 1600, a Mw/Mnratio of 1.1 to 2.7 and a softening point ranging from 0° C. to 40° C.The color of the resins of this invention range from less than about 1to about 7 on the well known Gardner scale even though the finishedresin has a vinyl aromatic content of from about 10 weight percent toabout 60 weight percent.

The resin of this invention is attractive and functional for use inadhesives since it has both a low softening point and light color inaddition to good tack and high compatibility with ethylene vinyl acetate(28-40% vinyl acetate) and other copolymers, both block and random.Heretofore, such a resin was not available.

The resin described above has been found to be compatible and producegood pressure sensitive adhesives, with many copolymers such as, forexample, styrene/isoprene/styrene (SIS), polyethylene vinyl acetate(EVA), styrene/butadiene/styrene (SBS), andstyrene/ethylene/butylene/styrene (SEBS), and the like. Generally, toprepare the adhesives of this invention, the copolymer is mixed withfrom about 20% to about 80% by weight of the resin with the copolymerbeing, correspondingly, about 80% by weight to about 20% by weight ofthe resin and the balance being optional components as hereinaftermentioned even though such optional materials are well recognized. Theseproportions will vary according to the copolymer involved, and therequirements of that copolymer to provide an adequate adhesive. Asoptional components, fillers and a hard resin having a softening pointof about 80° C. or higher can be added in amounts of from 0 to 60% byweight in order to impart additional strength to the final adhesive.Examples of such hard resins could be aliphatic resins,aliphatic/aromatic resins, aromatic resins, terpene resins, terpenealiphatic resins, rosins, rosin derivatives and hydrogenated derivativesof the foregoing resins, and the like. These resins are well known tothose skilled in preparing adhesives.

Detailed Description of the Invention

In practicing this invention to produce the novel, usually petroleumresins which have been found to provide tackification in many copolymerblends, the feedstock composition is important to obtain resinspossessing requisite molecular weight and distribution, softening pointand preferred color for a particular use. While the reaction conditionsare also important, they may be varied somewhat.

The resin of this invention, having a softening point from 0° C. toabout 40° C., and preferably from about 15° C. to about 30° C. and acolor less than about a Gardner color of 7 (determined in a 50/50solution with toluene) and preferably less than 5, most preferably aGardner color less than about 2, is formed from a feed containing a C₈to C₁₀ vinyl aromatic hydrocarbon stream, a heart cut distillate streamfrom steam cracked aromatic hydrocarbons having a boiling point range offrom about 80° C. to about 260° C. or, preferably, pure styrene monomer,substituted styrene monomers, or mixtures thereof, present in amounts offrom about 5% to about 75% by weight and preferably from about 5% toabout 50% by weight of the polymerization feed, for pressure sensitiveadhesive use preferably about 10% to about 40% by weight of thepolymerization feed.

Preferable ranges of the vinyl aromatic component depend largely uponthe end use involved and the desired properties of the resins. As notedabove, color depends, at least in part, on the purity of the aromaticstream. Thus, preferred applications where light color is needed dictatethat fewer impurities be present in the vinyl aromatic hydrocarbonstream even though the impurities are also hydrocarbons which act as adiluent in the reaction mixture and are removed after the resin isformed. When a resin having a softening point of from 15° C. to about30° C. and a Gardner color of about 2 or less is desired, the preferredrange of the vinyl aromatic component in the finished resin would befrom about 10 to about 60weight percent. The vinyl aromatic monomercontent of the feed to achieve this aromatic content in the resin isfrom about 5 to about 50 parts by weight in the feed.

Optionally included as the second component is up to about 35% byweight, preferably from about 10% to about 26% and most preferably fromabout 12% to about 16% by weight, of a piperylene concentrate resultingfrom the isolation of a fraction of steam cracked petroleum hydrocarbonswhich boils between about 20° C. to about 140° C., said fractioncontaining diolefins being substantially below the nine carbon atomlevel. Preferably, piperylene concentrates have long been used in thepreparation of resins along with the C₅ or C₆ olefins or diolefins, ormixtures thereof. Preferably, such fraction is heat soaked as is wellknown and described in U.S. Pat. No. 4,391,961, such disclosure beingincorporated herein by reference for all purposes. The piperyleneconcentrate hereinafter sometimes referred to as heat soakedpiperylenes, when incorporated into the resin of this invention, impartsa lower color to the resulting resin. While the piperylene concentratecan be used without heat soaking to produce the low softening pointresin, a heat soaking step improves color. Piperylene concentrates, aswill be shown later, contain hydrocarbons which do not enter into theresin-forming reaction. The presence of unreactive materials normally dono harm to the resin and, during reaction, act as a diluent to beremoved when the resin is recovered.

The other component of the resin feed stream is a chain transfer agentcomprising a stream containing C₄ to C₈ monoolefin chain transfer agentsof the general formula RR'C═CR"R"' where R and R' are C₁ to C₅ alkyl, R"and R"' are independently selected from H and C₁ to C₄ alkyl group.Useful chain transfer agents are, for example, isobutene, isoamylenes,isohexenes and diisobutenes. The isoamylenes particularly useful aredescribed in U.S. Pat. No. 4,514,554, disclosure of which isincorporated by reference herein for all purposes. These are usuallyconcentrates, or mixtures, containing the various isomers desired fromdistillation cuts, well known to those skilled in the art, as well asmixtures made from pure compounds.

Particularly useful as the chain transfer agent to prepare the resin ofthe instant invention is the mixture containing isohexene isomersresulting from the dimerization of propylene in the well known"Dimersol" process using a nickel coordination complex and an aluminumalkyl as catalyst. The process can convert propylene to hexenes withselectivity in excess of 85%. The Dimersol® dimerization process hasbeen referred to in various publications, e.g., see "How First Dimersolis Working" by Benedek et al., Hydrocarbon Processing, May 1980, page143; also Chauvin et al., "The IFP Dimersol® Process for theDimerization of C₃ and C₄ Olefinic Cuts", Advances in PetrochemicalTechnology, presented at American Institute of Chemical Engineers, Apr.13, 1976, Kansas City, Mo.

While it is known that the pure compounds and isomers making up theaforementioned C₄ to C₈ monoolefin chain transfer agent streams areuseful chain transfer agents, it is within the scope of the presentinvention to use mixtures of isomers and reaction products containingsuch isomers, in the practice of this invention, with the isohexenesproduced by the "Dimersol" dimerzation process being preferred.

Hexenes, as produced by dimerization of propylene with transition metalcatalyst, as in the Dimersol® dimerization process, are characterized bybeing composed mainly of internal olefins, and a linear content whichhas a range from about 20% up to 32% or so by weight. The main isomerpresent is a 2-methyl-2-penene, along with other 2- and 4-methylpentenes and around 6% 2,3-dimethyl-2-butene. Some C₉ trimer, about 15%is also produced in the process. While it is not necessary to separatethe C₉ trimer from the isohexene mix in the practice of this invention,it is preferred.

The chain transfer agent stream is present in the polymerizationreaction mixture in an amount of from about 25% to about 70% by weightwith 45% to about 65% by weight being preferred depending upon theproperties finally desired.

In carrying out the polymerization reaction, the hydrocarbon mixture isbrought into contact with a Friedel Crafts catalyst such as BF₃, BF₃etherates, AlCl₃, CH₃ CH₂ AlCl₂, or similar catalysts containingaluminum chloride or boron fluoride, with anhydrous aluminum chloridebeing preferred. Other Friedel Crafts catalysts may be used. Thecatalyst may be gaseous, liquid or solid. Generally, the catalyst isused in gaseous BF₃ or particulate AlCl₃ form having a particle size inthe range of from about 5 to about 200 mesh size, although larger orsmaller particles can be used. The amount of catalyst used ranges fromabout 0.5% to about 2.0% by weight, preferably 1.0% to 2.0% by weight.The catalyst may be added to the hydrocarbon mixture or the hydrocarbonmixture may be added to the catalyst. The reaction can be conductedcontinuously or by batch process techniques generally known to thoseskilled in the art.

The reaction should also be carried out at a pressure of from 10 psi(0.7 Kg/cm²) to 80 psi (56 Kg/cm²), preferably 20 (1.4 Kg/cm²), psi. Thetemperature of reaction ranges from about 20° C. to 100° C., moreusefully from 30° C. to 60° C., and most preferably from about 35° C. toabout 50° C. The time of polymerization ranges from one-fourth to 2.0hours, preferably from 20 minutes to 1 hour.

The reaction is conveniently carried out in the presence of a diluentbecause the reaction is usually exothermic and the resulting product isviscious. However, with adequate mixing and cooling, the temperature canbe controlled and reaction conducted with only sufficient diluent tomaintain good heat transfer for the heat of polymerization. The diluentmay be introduced as an integral component of the feedstock streams whenconcentrates, reaction mixtures or distillation fractions are used, butvarious other diluents which are inert in that they do not enter intothe polymerization reaction, may be separately added. Representativeexamples of inert diluents are aliphatic hydrocarbons such as pentane,hexane and heptane, aromatic hydrocarbons such as xylene, toluene andbenzene, and unreacted residual hydrocarbons from the reaction may beuseful as diluents.

After the polymerization is complete, the catalyst is quenched by wellknown means, usually by adding water and alcohol solution followed byresin recovery which involves stripping of unreacted hydrocarbons,including diluent from the resin as known by those skilled in preparingsuch resins. This "finishing" step is usually carried out by heating, ina nitrogen environment, usually to about 250° C., followed by streamstripping to remove unreacted material and low molecular weightoligomers ("fill"). The degree of stripping can be varied somewhat asdescribed to make small adjustments to the softening point.

The raffinate removed can be saved and used as the diluent for otherpolymerization reactions to form resins.

The resin obtained by the above-identified polymerization process usingthe feedstock herein described can have a wide variety of propertieswithin the scope of the aforesaid parameters (they will still have lightcolor and a low softening point between 0° C. and 40° C.) by varyingfeedstock selection. For example, if a Gardner color of 6 to 8 can betolerated, then (1) the vinyl aromatic feed stream can be derived from adistillation cut boiling in the range of from about 80° C. to about 260°C. from a stream cracked aromatic hydrocarbon stream; and (2) apiperylene concentrate (C₅ olefin and diolefin mixture) which is notheat soaked can be used. If slightly better color, i.e., Gardner 3 to 6is desired, then a styrene concentrate, i.e., a distillation streamcontaining predominantly styrene and its various substituted styrenematerials such as alpha-methylstyrene, para-methylstyrene orvinyl-toluenes may be used. Finally, if Gardner color less than 3 isdesired, then it is preferred to use pure styrene or substituted styrenemonomers, with styrene, alpha-methylstyrene or mixtures thereof beingpreferred. When these monomers or mixtures of pure monomers are usedwith a heat soaked piperylene concentrate, a preferred resin having acolor of 2 or less on the Gardner scale, a molecular weight distributionof from 1.15 to 1.25 and a softening point of from 15° C. to 30° C. canbe obtained. These are superior resins for use in adhesives. The resinsof this invention can be readily blended with copolymers using wellknown methods to form adhesives and find great use as such.

The resins of this invention can be readily prepared from the foregoingdescription and the following examples. Those skilled in preparingadhesives from petroleum hydrocarbon resins will be able to incorporatesame with copolymers. Accordingly, this invention is further describedby the following examples which are offered by way of explanation andfor the purposes of guiding those skilled in the art to the practice ofthis invention and the broadening of its usefulness and not for purposesof limitation thereof and it should not be so construed.

EXAMPLES 1-4

The liquid resins of Examples 1-4 were polymerized batchwise usingaluminum chloride catalyst in a nitrogen atmosphere at about 12 psig(0.84 Kg/cm²). The aluminum chloride catalyst (having particle sizebetween 5 and about 200 mesh) is added in anhydrous form. In thesepolymerizations, 400 grams of feed blend, in proportions indicated inTable 1, were pumped into a closed, stirred reactor containing catalyst,over a thirty minute period of time and then left in contact with thecatalyst for an additional thirty minutes with stirring. A 400 gram 1:3solution of isopropanal:water was added to the reaction mixture toquench the catalyst and the polymerizate was water washed two to threeadditional times with the aqueous phase being separated after each wash.

The polymerizate was finished by heating to 250° C. in a nitrogenatmosphere to remove unreacted material. The polymerizate was thenstream stripped at 250° C. to produce the finished resin.

In Examples 1-4, the xylenes, styrene, p-methylstyrene, mixed methylstyrenes and alpha-methylstyrene components were of at least 96% purity.The compositions of the heat soaked piperylene concentrate andisoamylene concentrate used are shown below:

    ______________________________________                                                       Piperylene                                                                             Isoamylene                                                           Concentrate                                                                            Concentrate                                           ______________________________________                                        Pentene-1        1.8        33.6                                              Pentene-2.sup.(1)                                                                              8.7        26.3                                              2 Methylbutene-1 0.1        29.6                                              2 Methylbutene-2 3.2         3.3                                              Cyclopentene     12.2       --                                                Pentadiene-1,3.sup.(1)                                                                         19.9       --                                                Low reactivity olefins and                                                                     54.1        7.2                                              nonreactive paraffins                                                         ______________________________________                                         .sup.(1) cis and trans isomers                                           

These examples show the influence of aromatic olefin structure on resinproperties. Resin properties are shown in Table 1 below:

                  TABLE 1                                                         ______________________________________                                        Example         1        2       3     4                                      ______________________________________                                        Feed Composition (part by weight)                                             Isoamylene Concentrate                                                                        50       →                                                                              →                                                                            →                               Piperylene Concentrate                                                                        21.4     →                                                                              →                                                                            →                               Styrene         28.6     --      --    --                                     P-Methylstyrene --       28.6    --    --                                     Mixed Methylstyrenes                                                          Meta-60%        --       --      28.6  --                                     Para-40%                                                                      Alpha-Methylstyrene                                                                           --       --      --    28.6                                   Xylenes         42.9     →                                                                              →                                                                            →                               Polymerization                                                                Catalyst wt %   1.4      →                                                                              →                                                                            →                               Reactor Temperature, °C.                                                               45       →                                                                              →                                                                            →                               Reactor Pressure, psig                                                                        12       →                                                                              →                                                                            →                               Resin Finishing                                                               Resin Yield, wt %                                                                             37.1     37.6    38.5  22.6                                   Resin Properties                                                              Softening Point, °C.                                                                   21       36      22.5  15                                     Cloud Point, °C.                                                                       <70      →                                                                              →                                                                            →                               20/40/40 (a)                                                                  Gardner Color (b)                                                                             3.5      3.5     4.5   6.5                                    GPC Molecular Weight                                                          Mn              135      197     142   125                                    Mw              210      403     232   195                                    Mw/Mn           1.56     2.05    1.63  1.56                                   ______________________________________                                         (a) The temperature at which there is an appearance of haze or "cloud" in     a mix of 40 parts 60° C. melt point paraffin wax, 20 parts of          Escorene ® 7750 (ethylene vinylacetate, 28% vinylacetate) from Exxon      Chemical Company and 40 parts test resin heated to 200° C. and         allowed to cool in air with stirring.                                         (b) 50 wt % resin solution in toluene with comparator discs.             

The ring and ball softening points of the resins were determined using amodified ASTM E-28 procedure. The softening point was measured in a50/50 ethylene glycol/water solution. The rings were kept in a -25° to-30° C. environment until the ethylene glycol/water solution was cooledto that temperature range. The ring and ball softening point apparatuswas assembled and heated at 5° C./min. The softening point temperaturewas then read according to the ASTM E-28 procedure.

EXAMPLES 5-13

Examples 5-13, a styrene concentrate fraction of steam cracked naphthaboiling within the range of from 80° C. to 190° C. was used with theisoamylene and piperylene concentrate to prepare resins in the mannerdescribed in Examples 1-4 about in proportions as set forth in Table 3.The compositions of the styrene concentrates are shown in Table 2 below:

                  TABLE 2                                                         ______________________________________                                        COMPOSITION OF STYRENE CONCENTRATES                                           Component       I          II     III                                         ______________________________________                                        Ethyl Benzene    4.6        2.6    6.5                                        o, m, p-Xylene  30.3       24.8   40.5                                        Styrene         28.8       26.5   33.6                                        Alpha-Methylstyrene                                                                            3.0        4.3    1.2                                        Vinyl Toluenes   5.1        7.6    1.5                                        Other Alkyl-substituted                                                                       28.2       34.2   16.7                                        Benzenes                                                                      ______________________________________                                    

These resins were polymerized and finished, and the softening pointswere determined using the same procedures discussed in Examples 1-4.These examples show the effect of varying feed blend ratios on resinproperties. Note the high color and softening points of certain resinsderived from the styrene concentrates.

Examples 10, 12 and 13 show the effect of styrene concentratecomposition on resin properties.

                                      TABLE 3                                     __________________________________________________________________________    Example     5   6   7   8   9   10  11  12  13                                __________________________________________________________________________    Feed Composition, parts by weight                                             Isoamylene  35  20  15  --  70  55  40  55  55                                Concentrate                                                                   Piperylene  15  30  15  30  --  15  30  15  15                                Concentrate                                                                   Styrene     50  50  70  70  30  30  30  --  --                                Concentrate I                                                                 Styrene     --  --  --  --  --  --  --  30  --                                Concentrate II                                                                Styrene     --  --  --  --  --  --  --  --  30                                Concentrate III                                                               Polymerization                                                                Catalyst, wt %                                                                            1.4 2.0 2.0 1.4 1.4 2.0 1.4 1.4 1.0                               Reactor     45  →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                          Temperature °C.                                                        Reactor     12  →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                                                                          →                          Pressure, psig                                                                Resin Finishing                                                               Resin Yield wt %                                                                          29.1                                                                              31.2                                                                              33.2                                                                              29.8                                                                              13.6                                                                              21.4                                                                              24.8                                                                              29.3                                                                              29.5                              Resin Properties                                                              Softening   38  50  50  64  20  29  40  21  13                                Point, °C.                                                             Gardner Color                                                                             10  10.5                                                                              11.5                                                                              11  12  10.5                                                                              8.5 10  6                                 GPC Molecular Weight                                                          Mn          175 167 141 156 194 183 200 304 280                               Mw          344 349 361 419 287 333 304 432 372                               Mw/Mn       1.97                                                                              2.09                                                                              2.56                                                                              2.69                                                                              1.48                                                                              1.82                                                                              1.52                                                                              1.42                                                                              1.33                              __________________________________________________________________________

EXAMPLES 14-20

In Examples 14-20, a mixed C₆ monoolefin stream prepared from thedimerization of propylene was used in place of isoamylene concentrate inresins produced as described in Examples 1-4 above. Typical compositionsof the C₆ olefin stream and the piperylene concentrate used in theseexamples follow:

    ______________________________________                                        Typical Composition of Mixed C.sub.6 Olefin Stream, %*                        2-Methyl-1-Pentene  3.9                                                       2-Methyl-2-Pentene  25.9                                                      2,3-Dimethyl-1-Butene                                                                             2.8                                                       2,3-Dimethyl-2-Butene                                                                             2.7                                                       Other C.sub.6 Olefins                                                                             50.5                                                      C.sub.9 Olefins     14.2                                                      Typical Composition of Heat Soaked Piperylene Concentrate, %                  1-Pentene           2.5                                                       Cis and trans-2-Pentene                                                                           6.5                                                       2-Methyl-1-Butene   0.2                                                       2-Methyl-2-Butene   3.7                                                       Cyclopentene        17.4                                                      Cis and trans-Piperylene                                                                          28.8                                                      Low reactivity olefins and                                                                        40.9                                                      nonreactive paraffins                                                         ______________________________________                                         *"Dimate", from Diamond Shamrock, produced by dimerization of propylene. 

In these Examples, pure styrene and alpha-methyl-styrene monomers wereused as the vinyl aromatic hydrocarbon stream resulting in resins havingan aromatic content from about 10 weight percent to about 60 weightpercent and a Gardner color of about 1. The feedstock composition andresin properties are shown in Table 4 below. These resins areparticularly useful to prepare adhesives in the practice of thisinvention.

                                      TABLE 4                                     __________________________________________________________________________    Example         14  15  16  17  18  19  20                                    __________________________________________________________________________    Feed Composition, Parts by wt.                                                C.sub.6 Olefins 69.4                                                                              36.5                                                                              59.5                                                                              59.5                                                                              50.8                                                                              66  43.9                                  ("Dimate")                                                                    Piperylene      25.2                                                                              13.7                                                                              22.5                                                                              22.5                                                                              19  24  16.4                                  Concentrate (1)                                                               Styrene         3.6 32.6                                                                              12  18  25.4                                                                              6.7 32.9                                  Alpha-Methylstyrene                                                                           1.8 17.1                                                                              6   --  4.8 3.3 6.8                                   Paraffinic Diluent                                                                            --  46.2                                                                              49.2                                                                              --  58.7                                                                              --  37.0                                  Polymerization                                                                Catalyst, wt %  1.2 1.2 1.2 1.2 1.2 1.2 1.5                                   Reactor         40  40  40  40  40  40  40                                    Temperature, °C.                                                       Reactor Pressure,                                                                             10  10  10  10  10  10  10                                    psig                                                                          Resin Finishing                                                               Resin Yield, wt %                                                                             24  50  30  37  36  28.3                                                                              46.3                                  Fill, wt %      1   --  4   4   4   7.1 4.3                                   Resin Properties                                                              Softening Point, °C.                                                                   20  21  17  23.5                                                                              24  23.5                                                                              29                                    Cloud Point, °C.                                                                       66  65  65  65  69  65  65                                    Gardner Color   1+  1+  1+  1+  1+  1-  1-                                    Vinyl Aromatic  12  59  34  --  45  25  51                                    Content, wt %                                                                 GPC Molecular Weight                                                          Mn              426 362 445 396 472 399 406                                   Mw              521 443 522 453 578 467 499                                   Mw/Mn           1.22                                                                              1.22                                                                              1.17                                                                              1.14                                                                              1.22                                                                              1.17                                                                              1.23                                  __________________________________________________________________________     (1) Heat soaked                                                          

EXAMPLES 21-23

In these Examples, the mixed C₆ monoolefin stream prepared from thedimerization of propylene was used again in the monomer described forthe examples above. However, in Example 21 no piperylene was used; inExample 22 an ethyl aluminum dichloride catalyst was used; and inExample 23 a BF₃ O(CH₂ CH₃)₂ (etherate) catalyst was used for FriedelCrafts polymerization. The feedstock composition and resin propertiesare shown in Table 4A below.

                  TABLE 4A                                                        ______________________________________                                        Example            21      22       23                                        ______________________________________                                        Feed Composition, Parts by wt.                                                C.sub.6 Olefins    25.0    59.5     56.3                                      ("Dimate")                                                                    Piperylene         --      22.5     22.0                                      Concentrate (1)                                                               Styrene            24.0    12.0     21.7                                      Alpha-Methylstyrene                                                                              11.0    6.0      --                                        Paraffinic Diluent 40.0    --       --                                        Polymerization                                                                Catalyst, wt %     1.2     1.2      1.0                                       Reactor            40      40       40                                        Temperature, °C.                                                       Reactor Pressure,  10      10       10                                        psig                                                                          Resin Finishing                                                               Resin Yield, wt %  47.0    41.4     30.5                                      Fill, wt %         7.9     2.7      12.9                                      Resin Properties                                                              Softening Point, °C.                                                                      18      21.5     18                                        Cloud Point, °C.                                                                          65      65       65                                        Gardner Color      1+      4+       1-                                        Vinyl Aromatic     64      34       50                                        Content, wt %                                                                 GPC Molecular Weight                                                          Mn                 355     392      290                                       Mw                 434     479      407                                       Mw/Mn              1.22    1.22     1.4                                       ______________________________________                                         (1) Heat soaked                                                          

EXAMPLES 24-26

In Examples 24-26, a heart cut distillate (80° C. to 260° C.) derivedfrom steam cracked naphtha was used in place of the pure vinyl aromaticmonomers in resins produced as described in Examples 1-4 above. Atypical composition of this heart cut distillate is shown below.

    ______________________________________                                        Typical Composition of Heart Cut Distillates: wt %                            ______________________________________                                        Styrene                7.2                                                    Vinyl Toluenes         13.9                                                   Alpha-Methyl styrene   3.8                                                    Beta-Methyl styrene    3.1                                                    Indene                 12.1                                                   Non reactive Aromatics and Alkyl                                                                     59.9                                                   substituted Aromatics                                                         ______________________________________                                    

The feedstock compositions and resin properties are shown in Table 5below:

                  TABLE 5                                                         ______________________________________                                        Example             24      25       26                                       ______________________________________                                        Feed Composition (parts by weight)                                            C.sub.6 Olefins     55      45       58.8                                     Piperylene Concentrate (1)                                                                        15      10       23.5                                     Heart Cut Distillate                                                                              30      45       17.6                                     Polymerization                                                                Catalyst, wt %      1.4     1.4      1.2                                      Reactor Temperature, °C.                                                                   40      40       40                                       Reactor Pressure, psig                                                                            10      10       10                                       Resin Finishing                                                               Resin Yield, wt %   40.7    46.6     29.6                                     Fill, wt %          --      --       7.6                                      Resin Properties                                                              Softening Point, °C.                                                                       23      26       21                                       Cloud Point, °C.                                                                           66      65       65                                       Gardner Color       6+      7        4+                                       Vinyl Aromatic Content, wt %                                                                      37      49       22                                       GPC Molecular Weight                                                          Mn                  504     428      423                                      Mw                  705     571      518                                      Mw/Mn               1.40    1.35     1.22                                     ______________________________________                                         (1) Heat Soaked                                                          

Better color (i.e., a lower Gardner number) could be achieved in theabove formulation if the heart cut distillate were acid treated usingknown methods.

EXAMPLES 27 AND 28

In the manner described in Examples 1-4, Examples 27 and 28 demonstratethe use of diisobutene and an isoamylene concentrate to prepare resinswithin the scope of the invention. The resin of Example 27 was strippedexcessively, resulting in a softening point of 41° C. If excessive hadnot occurred, the softening point would have been 40° C. or less with aGardner color of about 2 also resulting. The results of theseexperiments are shown in Table 6:

                  TABLE 6                                                         ______________________________________                                        Example              27      28                                               ______________________________________                                        Feed Composition, Parts by wt.                                                Styrene              16.3    12.0                                             Alpha-Methylstyrene  8.2     6.0                                              Heat Soaked piperylenes                                                                            30.6    22.5                                             Diisobutene          44.9    --                                               Isoamylene           --      59.5                                             Diluent              104.1   27.2                                             Polymerization                                                                Catalyst, wt %       1.2     1.2                                              Reactor Temperature, °C.                                                                    40      40                                               Reactor Pressure, psig                                                                             10      10                                               Resin Finishing                                                               Resin Yield, wt %    27.4    44.3                                             Fill, wt %           12.0    --                                               Resin Properties                                                              Softening Point, °C.                                                                        41      10                                               Cloud Point, °C.                                                                            65      65                                               Gardner Color        4+      1                                                Resin Molecular Weight, GPC                                                   Mn                   519     356                                              Mw                   619     400                                              Mw/Mn                1.19    1.12                                             ______________________________________                                    

The low softening point liquid resins described above are all applicablein the practice of the instant invention to make adhesives when combinedwith a copolymer. The copolymers useful for the practice of thisinvention are generally known as, for example, styrene/isoprene/styrene(SIS), polyethylene vinyl acetate (EVA) (from about 25% to about 45% byweight vinyl acetate), styrene/butadiene/styrene (SBS) andstyrene/ethylene/butylene/styrene (SEBS), and the like. Of particularinterest are the styrene/butadiene copolymers which are more difficultto tackify than other polymers using a resin and often require not onlya tackifier but an oil to act as a plasticizer thus giving rise to theproblem of "bleed" and/or "creep" when the adhesive is applied to apaper or polymer substrate. When the need is for a light color,essentially water white resin, previously only resins prepared fromnonaromatic materials were available since aromaticity had heretoforeimparted color to the resin which was unacceptable for certainapplications, including premium packaging and disposable diapers. Thepresence of an oil in the adhesive composition has other detrimentaleffects such as unacceptable creep and bond release along a polyethylenefilm, particularly in a case where disposable diapers are involved.Thus, the resins described above, particularly those of Examples 14-20which can be used with styrene/butadiene polymers in a binary system,i.e., by eliminating the plasticizer, are particularly useful.

Well known styrene/butadiene copolymers useful in the practice of thisinvention are those sold by Shell under the "Kraton" trademark and bythe Firestone under the "Stereon" trademark. Both of those arestyrene/butadiene copolymers which form particularly attractiveadhesives when used in combination with the above-identified resins,particularly the very low color resins of Examples 14-20 having asoftening point of around 20° C. The "Stereon" copolymer grade 840A is acopolymer containing 42% styrene. In formulating the adhesive, theliquid resin is present in amounts from 20% to 80% by weight with thecopolymer present in, correspondingly, 80% to 20%. The preferredadhesive would contain from about 30% to about 70% by weight of theresins with from about 35% to about 50% by weight in the adhesive beingespecially preferred. In binary adhesives, the copolymer will be presentin corresponding amounts. However, other components may be present.Optionally, a resin having a higher softening point, from about 80° C.to about 120° C., may be used as an additional component of the adhesivecomposition. While the preferred adhesive is a binary system comprisingtwo reactants, the copolymer and the light color resins describedherein, such binary system may still include such nonreactiveingredients as fillers, inhibitors, and the like. Representative offillers would be, for example, calcium carbonate, titanium oxides,finely divided clays, talc and the like.

Once blended using methods and techniques well known to those skilled inthe art, the adhesive would be coated on a substrate such as "Mylar"film (Dupont Company) or "Endura" film (Akrosil). The adhesive is thenevaluated in terms of those parameters important to adhesives such asrolling ball tack, polyken tack, peel strength, holding power and agedretention of these properties.

The adhesive compositions of the present invention may be applied to asubstrate and, if solvent coated, dried using conventional procedures.The substrate used depends upon the anticipated use, but it is usuallyrelatively thin material, usually no greater than about 3.2 mm inthickness, and in the manufacture of tapes and labels, the substrate isa relatively thin sheet material. The sheet material may be a polymericmaterial which is flexible at about room temperature. The sheet materialmay be a homo-polymer of an ethylenically unsaturated monomer such asethylene, propylene or vinyl chloride, or be polyester, polyacetate orpolyamide provided it has sufficient flexibility for the desired enduse. Alternatively, the substrate may be made from cellulosic orreconstituted cellulosic material such as rayon. The substrate need notbe a sheet material but may be composed of fibers which may be woven, ornonwoven as is the case in paper. Woven substrates may be made fromcellulosic material, such as cotton or from fibers of any of the abovementioned polymers.

The composition is applied to the substrate using conventional coatingtechniques such as roller coaters, blade coaters, meyer rods or aircoaters. The coated substrate can be dried usually by passing it througha heating tunnel or oven through which may be circulating hot air or thetunnel or oven may contain infrared lamps to dry the coated substrate.The drying time will be a function of a number of factors such as theheat capacity of the substrate, the type of heating, the oventemperature, air velocities (if circulating air is used) and the rate ofpassage of the substrate through the heater.

The substrate should be coated with sufficient composition to provide adry coat weight from about 16 to about 57 g/m². Generally in themanufacture of tapes using a continuous sheet polymeric substrate, a drycoat weight of about 15-30 g/m² is used. In the manufacture of labels, adry coat weight from about 15 to 30 g/m² is usually used. In themanufacture of masking tape, a dry coat weight from about 35 to about 65g/m² is usually used.

After drying, the coated substrate is cut to the required dimension. Inthe manufacture of tape, the substrate is cut into strips and rolled toprovide a finished product. The substrate may also be cut into shapeditems to provide labels or medicinal tapes.

One particularly attractive use for the pressure sensitive adhesives ofthe present invention is in diaper tabs for disposable diapers,particularly repositional tabs which employ a "Mylar" polymer substratecoated as stated above with 1.5 mil adhesive as shown in Table 7 below.

                  TABLE 7                                                         ______________________________________                                        Adhesion Testing of Commercial Disposable Diaper Tabs                                          Commercial Commercial                                        Product          Tab "1"    Tab "2"                                           ______________________________________                                        Polyken Tack (g)                                                              Initial          291        407                                               Aged (2)         451        487                                               180° Peel Strength (lb/in) (1)                                         Stainless Steel                                                               Initial          6.28       5.75                                              Aged (2)         6.00       2.25                                              Polyethylene (3)                                                              Initial          1.63       1.63                                              Aged (2)         1.40       0.80                                              Repeat Polyethylene (4)                                                       Initial          1.67       SF (6)                                            Aged (2)         1.50       1.23                                              Loop Tack (lb/in)                                                             Stainless Steel                                                               Initial          3.42       2.42                                              Aged (2)         0.75       2.00                                              178° Holdind Power, (5) (hrs.)                                         Stainless Steel                                                               Initial          2.61       14.99                                             Aged (2)         0.26       13.11                                             ______________________________________                                         (1) 1.5 mil drawdown on 0.01 g/cm.sup.2 backing                               (2) Aging Conditions: 2 weeks at 158° F.                               (3) 10 mil polyethylene film (from Tab "1")                                   (4) 2 hours at room temperature                                               (5) 1/2" × 1/2", l kg                                                   (6) Substrate Failure                                                    

The mechanical preparation of the adhesives of this invention are wellknown to those skilled in the art. In addition to the components whichmake up the adhesives of this invention, i.e., the copolymers and thelow softening, light color resin described above, other materials, wellknown to those skilled in the art may be added without departing fromthe invention such as, for example, fillers or resins having highermelting points such as, for example, from about 80° C. to about 120° C.in order to impart additional strength to the resulting pressuresensitive adhesive. In some applications, it may be desirable to add upto about 60 weight percent of "hard" resin such as that described inU.S. Pat. No. 4,514,554 for example, the disclosure of which isincorporated herein by reference, and U.S. Pat. No. 4,391,961. Bothprovide often desirable modifications of the pressure sensitive adhesiveof this invention.

Preferred adhesives are made with a styrene/butadiene copolymer havingfrom about 40% to about 50% styrene. In use, the adhesives are appliedto a polyacetate or cellulose backing in a thickness of from 0.7 to 1.5mil. To illustrate the present invention, adhesives were made by mixinga styrene/butadiene copolymer having 42% styrene polymer ("Stereon"Resins from Firestone) with resins similar to, and prepared in the samemanner as, those of Examples 16 and 18 and commercially available resinsuseful to produce adhesives with such styrene/butadiene copolymer. Thecharacteristics of the liquid resins compared are set forth in Table 8.

                                      TABLE 8                                     __________________________________________________________________________    Comparison of Liquid Resins with                                              Styrene/Butadiene Copolymer (Stereon ® 840A)                                        Exp 16                                                                              Exp 18                                                                              Regalrez                                                                              Hercolyn                                                                            Zonarez                                                                             Wingtack                                      (34%  (45%  1018    D     A-25  10                                            Aromatic)                                                                           Aromatic)                                                                           (Hercules)                                                                            (Hercules)                                                                          (Arizona)                                                                           (Goodyear)                          __________________________________________________________________________    Type      Aromatic/                                                                           Aromatic/                                                                           Hydrogenated                                                                          Rosin Terpene/                                                                            Aliphatic                                     Aliphatic                                                                           Aliphatic                                                                           Aromatic                                                                              Ester Oil                                       Softening 22    24    17      0     20    8.5                                 Point (°C.)                                                            Cloud     97    100   100     98    97    109                                 Point(1)                                                                      Viscosity                                                                     (cps)                                                                         100° F.                                                                          22950 24000 17750   895   20100 5713                                200° F.                                                                          99    123   83      19    67    58                                  Gardner Color(2)                                                              Initial   2-    1.5   <1      2+    2+    1                                   Aged (16  4+(3) 5-(3) 2-      11    13-   9+                                  Hrs/300° F.)                                                           Mw        577   518   383     252   416   623                                                               (bimodal)                                                                           (trimodal)                                Mn        492   518   346     235   346   531                                 Mw/Mn     1.17  1.17  1.11    1.07  1.20  1.17                                Volatility                                                                    (wt % loss)                                                                   10 g/5 Hr/                                                                              6-7   6-7   11.3    >20   18.1  14.1                                350° F.(4)                                                             __________________________________________________________________________     (1)Multiwax 195 (microcrystalline wax  M.P. 195° F.)  33 wt %;         Elvax 150 (EVA  M.P. 150° F.)  27; Resin  40 wt %                      (2)50% in toluene.                                                            (3)Inhibited with Irganox 1010 at 0.15 wt %.                                  (4)3" diameter aluminum dish.                                            

These resins as shown are used in preparing a repositional diaper tab invarying proportions of resin to copolymer in the manner of mixing wellknown to those skilled in the art. The adhesive was applied in theamount of 1.5 mil drawdown on 0.005 g/cm² "Mylar" polyacetate filmbacking. The test results are as shown in Table 9 and Table 10.

                                      TABLE 9                                     __________________________________________________________________________    LIQUID RESINS COMPARISONS                                                     PERFORMANCE IN STEREON 840A COPOLYMER                                         REPOSITIONABLE DIAPER TABS                                                                             Aging Conditions: 2 weeks at 158° F.                                   1.5 ml drawdown on .005 g/cm.sup.2 mylar             __________________________________________________________________________                             backing                                                                               Loop Tack                                                                             178° Holding Power            Formulation (1) Rolling Ball Tack                                                                      Polyken Tack                                                                          lb/in   hr                                   wt %            cm       g       SS      SS, 1/2" × 1/2", 1 kg                Copolymer                                                                           Resin                                                                             Initial                                                                            Aged                                                                              Initial                                                                           Aged                                                                              Initial                                                                           Aged                                                                              Initial                                                                            Aged                            __________________________________________________________________________    Resin of                                                                            80    20  >30.0                                                                              >30.0                                                                             <10 <10 <.01                                                                              <.01                                                                              >100.0                                                                             0.0                             Example 16                                                                          65    35  7.2  8.8 174 237 0.13                                                                              0.12                                                                              >100.0                                                                             >100.0                                50    50  3.1  2.0 812 718 0.85                                                                              0.72                                                                              >100.0                                                                             2.6                                   35    65  2.7  2.3 997 1000                                                                              3.41                                                                              1.08                                                                                2.6                                                                              0.3                                   20    80  2.4  2.3 1357                                                                              1192                                                                              3.29                                                                              2.90                                                                                0.4                                                                              0.3                             Zonarez                                                                             80    20  >30.0                                                                              >30.0                                                                             < 10                                                                              <10 <.01                                                                              <.01                                                                              >100.0                                                                             0.0                             A-25  65    35  4.7  12.7                                                                              262 205 0.15                                                                              0.17                                                                              >100.0                                                                             >100.0                                50    50  3.1  3.3 659 468 0.27                                                                              0.62                                                                              >100.0                                                                             3.4                                   35    65  2.5  2.1 721 602 0.55                                                                              0.95                                                                                0.9                                                                              0.4                                   20    80  2.3  2.7 843 736 1.20                                                                              0.62                                                                                0.2                                                                              0.2                             Regalrez                                                                            80    20  >30.0                                                                              >30.0                                                                              71 <10 <.01                                                                              <.01                                                                              >100.0                                                                             0.0                             1018  65    35  5.6  9.4 457 198 0.50                                                                              0.16                                                                              >100.0                                                                             >100.0                                50    50  3.2  2.8 948 685 1.08                                                                              0.93                                                                              >100.0                                                                             2.6                                   35    65  2.5  2.2 1009                                                                              1017                                                                              1.43                                                                              1.50                                                                                0.6                                                                              0.5                                   20    80  1.7  2.6 1103                                                                              940 3.29                                                                              1.95                                                                                0.5                                                                              0.5                             __________________________________________________________________________                    180° Peel Strength                                                     lb/in                                                         Formulation (1)                   Repeat Polyethylene                         wt %            Stainless Steel (SS)                                                                    Polyethylene (2)                                                                      2 hrs                                             Copolymer                                                                           Resin                                                                             Initial                                                                            Aged Initial                                                                           Aged                                                                               Initial                                                                           Aged Staining                          __________________________________________________________________________    Resins of                                                                           80    20  0.63 0.00 0.00                                                                              0.00                                            Example 16                                                                          65    35  0.30 0.08 0.00                                                                              0.00                                                  50    50  2.40 1.80 0.68                                                                              0.23                                                                              0.70 0.24 None                                    35    65  2.82 2.02 0.95                                                                              0.72                                                                              0.98 0.70 Slight                                  20    80  7.47 7.38 SF (3)                                                                            1.65     SF                                     Zonarez                                                                             80    20  0.00 0.00 0.00                                                                              0.00                                            A25   65    35  0.32 0.00 0.00                                                                              0.00                                                  50    50  1.15 0.48 0.30                                                                              0.00                                                                              0.70      None                                    35    65  1.45 0.77 0.50                                                                              0.00                                                                              0.80      Heavy                                   20    80  3.19 1.33 SF  0.25     0.35                                   Regalrez                                                                            80    20  0.17 0.00 0.00                                                                              0.00                                            1018  65    35  1.18 0.17 0.00                                                                              0.00                                                  50    50  1.92 1.53 0.65                                                                              0.25                                                                              0.58 0.15 None                                    35    65  2.58 1.88 0.93                                                                              0.77                                                                              1.50 0.80 Slight                                  20    80  6.18 4.83 SF  0.70     SF                                     __________________________________________________________________________     (1) Includes 0.5 wt % Irganox 1010                                            (2) 1 ml thick polyethylene (PE) film from Commercial Tab                     (3) Substrate Failure                                                    

To further demonstrate the advantages of this invention, a pressuresensitive adhesive is described below using the above described liquidresin, the styrene/butadiene copolymer, and a commercially availableinhibitor. The 20° C. softening point liquid resin is similar to the onedescribed in Examples 10 and 12 with the properties as shown in Table 8.

                  TABLE 10                                                        ______________________________________                                         REMOVABLE PRESSURE SENSITIVE ADHESIVES                                       ______________________________________                                                           parts by wt.                                                                             parts by wt.                                    ______________________________________                                        Liquid Resin from Examples 16                                                                    60         67                                              and 18                                                                        Stereon ® 840A styrene-butadiene                                                             40         33                                              copolymer (42% Styrene)                                                       Irganox ® 1010 inhibitor                                                                     0.5        0.5                                             ______________________________________                                                        Initial Aged     Initial                                                                             Aged                                   ______________________________________                                        Rolling Ball Tack (cm)                                                                        3.0     3.5      2.8   3.1                                    Polyken Tack (g)                                                                              664     491      770   521                                    180° Peel Strength (lb/in)                                             to SS           1.48    1.07     1.44  1.79                                   to PE (10 mil, untreated)                                                                     1.00    0.42     1.15  1.13                                   Loop Tack (lb/in)                                                             to SS           0.35    0.35     0.66  0.75                                   To PE (10 mil, untreated)                                                                     0.60    0.68     0.28  0.56                                   SAFT to SS (°F.)                                                                       132     123      123   126                                    178° Holding Power (hrs)                                                               9.5     27.9     3.9   3.7                                    (1/2" × 1/2" × 2,000 g)                                           ______________________________________                                    

As seen from the foregoing, the pressure sensitive adhesive of thepresent invention provides considerable advantage over other pressuresensitive adhesives made with available liquid resins.

EXAMPLE 29

Hydrogenation of the resins of the invention results in a colorimprovement. A resin very much like that of Example 24 and Table 5 washydrogenated by dissolution of the resin in an inert, predominantlysaturated hydrocarbon solvent (Varsol) at 30 wt. % concentration andpassing the solution over a sulfided nickel/tungsten/alumina catalyst.The flow rate was 1.5 VVH, hydrogenation pressure 3000 psi and inlettemperature 270 degrees C. The hydrogenated solution was stripped togive a 28.3% yield of product with a color of 28 Saybolt (measured as10% solution in toluene; water white resin is 30 Saybolt) and softeningpoint of 19 degrees C. The GPC molecular weight was indicated to be thesame as for the resin of Example 24 both before and after hydrogenation.The vinyl aromatic content dropped slightly to about 22%. Thehydrogenated resin has proven to be an excellent water white tackifierin various adhesive formulations as described above.

Other suitable catalysts for hydrogenation include nickel and palladiumbased catalysts preferably supported on alumina or similar material.Hydrogenation temperatures and pressures can be much lower than as givenin the example, or higher as needed depending on the catalyst.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in thecomponents, parameters and proportions, as well as in the details of theillustrated examples, may be made without departing from the spirit andscope of the claimed invention.

We claim:
 1. A hydrocarbon resin having a softening point of from 0° C.to about 40° C., a Gardner color of about 7 or less, a number averagemolecular weight (Mn) of from about 100 to about 600, and a M_(w) /M_(n)ratio of from about 1.1 to about 2.7, prepared by Friedel Craftspolymerization of a hydrocarbon feed comprising:(a) from about 5% toabout 75% by weight of a C₈ to C₁₀ vinyl aromatic hydrocarbon stream;(b) up to about 35% by weight of a piperylene stream; and (c) from about25% to about 70% by weight of a stream containing C₄ to C₈ monoolefinchain transfer agent of the formula RR'C═CR"R"' where R and R' are C₁ toC₅ alkyl, R" and R"' are independently selected from H and a C₁ to C₄alkyl group.
 2. A resin according to claim 1 prepared by aluminumchloride catalyzed polymerization.
 3. A resin according to claim 1wherein the C₈ to C₁₀ vinyl aromatic hydrocarbon stream is a distillatefraction from steam cracked aromatic hydrocarbon having a boiling pointrange of from about 80° C. to about 260° C.
 4. The resin according toclaim 1 wherein the piperylene stream is present in the hydrocarbon feedin amounts of from about 10% to about 35% by weight.
 5. The resinaccording to claim 1 wherein the piperylene stream is a heat soakedpiperylene.
 6. The resin according to claim 1 wherein the chain transferagent stream is present in amounts of from about 45% to about 65% byweight.
 7. The resin according to claim 1 wherein the chain transferagent stream is a mixture of C₆ isomers produced by the dimerization ofpropylene.
 8. The resin according to claim 1 wherein the hydrocarbonfeed comprises:(a) from about 5 to about 50 parts by weight of styrene,alpha-methyl styrene, or mixtures thereof; (b) from about 10 to about 26parts by weight of a heat soaked piperylene stream; and (c) from about25 to about 70 parts by weight of a mixed C₆ olefin stream produced bydimerization of propylene.
 9. The hydrocarbon resin of claim 1 having asoftening point of from about 15° C. to about 30° C.
 10. A petroleumhydrocarbon resin having a softening point of from 10° C. to about 30°C., a Gardner color of 2 or less and a molecular weight distribution offrom about 1.1 to about 1.3 with number average molecular weight of fromabout 350 to about 500; prepared by Friedel Crafts polymerization from areaction mixture comprising:(a) from about 5 to about 50 parts by weightof styrene, alpha-methyl styrene or mixtures thereof; (b) from about 10to about 26 parts by weight of a heat soaked piperylene concentrate; and(c) from about 25 to about 70 parts by weight of a stream containingmixed C₆ monoolefins resulting from the dimerization of propylene.